Localization, or the determination or estimation of the location of an electronic device, often involves the use of Global Positioning System (GPS) circuitry operating at the device. The device may receive GPS data from a number of GPS satellites, and process that received data to determine a location of the device. However, in some environments, such as inside buildings, parking garages, or other obstructions to satellite signals, the device may not be capable of receiving the GPS data.
Various forms of radio frequency (RF) localization may be employed instead of GPS localization to locate a device in such environments. Oftentimes, in such systems, a characteristic of a communication signal received from the device, such as the Received Signal Strength Indicator (RSSI), is used to determine a location of the device relative to a “reference point” device, such as one or more signal readers, wireless access points, or infrastructure devices designed specifically for localization of devices. The accuracy of such systems is typically enhanced by increasing the number of reference points.
Such localization systems also often employ a “fingerprinting” or “site surveying” operation prior to being placed into service for RF localization of actual user devices. During the fingerprinting or site surveying, a test device that transmits a signal may be moved throughout an area proximate the reference points, typically along a predetermined path, to provide reference information against which received signals from user devices are compared to localize those devices. Structural changes in the area of interest, such as location and/or orientation changes in walls, partitions, barriers, and furniture, often reduce the accuracy of a previous fingerprint or survey of the area, indicating that another fingerprinting or surveying operation may be beneficial. Further, temporary changes in the RF environment in the area of interest, such as the presence of people, may alter the reach or strength of the communication signals received at the reference points from the user devices, thus complicating the task of determining the location of the devices relative to the reference points.